A general object of the invention is to provide in a warded, insert-equipped padlock, means for receiving the operating key including a web on the bottom of the plug extension formed with cuts or notches and nodules matching special cuts and/or notches and nodules in and on the tip of the key shank whereby turning movement of the special key is effective to turn the plug extension for shackle releasing purposes.
Further objects of the invention are to provide in a warded insert-equipped key operated padlock, novel co-acting means between the tip of the special operating key and the bottom of the plug extension which function efficiently and automatically, in which the mechanism of a certain lock is responsive only to the tip formation of the special key therefor, and in which the key tips for different locks may have a pair of different tip dispositions.